Portable devices are used widely for many different purposes. For example, laptop computers are used for tasks such as word processing, performing calculations, maintaining calendar information, printing information, sending and receiving e-mails, etc. For such purposes there are different kinds of applications (programs) installed on the portable device. When an application of the portable device needs to communicate with another device, e.g. a phone, a printer and/or a modem, the portable device is connected to the other device e.g. with a cable or with wireless means. In addition to that a software module is installed to the portable device for providing a suitable interface for the connection in question. Then, the software module can be used to perform necessary conversions between signals of the application and the other device. Not all the connections are of the same type. For example, a phone needs a different kind of communication than a modem. Therefore, the interface converts the messages sent from the application to messages and/or signals suitable for commanding the device in question. The interface also converts the incoming messages and/or signals to a form which is understandable by the application.
Nowadays, new mobile phones offer a lot more functionality than just the ability to talk. There are mobile phones which include calendar operations, word processing operations, calculation operations, etc. However, because of the limited size of the mobile phones they are not so easily operated as larger devices, e.g. laptop computers. Therefore, there is a need to connect mobile phones with another device for performing operations of the mobile phone by using the device connected to the mobile phone. Different connection types have been developed for such arrangements. There are, just a few to mention, wired connections by using e.g. RS-232, USB (Universal Serial Bus), and wireless connections by using optical signals (e.g. IrDA), inductive signals, and/or radio signals (e.g. Bluetooth™, WLAN). Each of these connection types have their own specifications. From the viewpoint of an application developer it is a demanding task to develop a proper interface for each of these connection types. In prior art the problem has been resolved by providing a certain media module in which all connection types to be supported by the media module have been taken into account. When a certain connection type has been taken into use, the media module has selected the proper interface which performs the necessary conversion operations between the application and the device in question. The media module is informed of the right connection type for the selection of the interface, for example, by the user of the portable device, or by some kind of handshaking procedure between the media module and the connected device.
One disadvantage with prior art systems is that there can only be one active connection at a time. So, if the user of the portable device would like to use two or more different connection types simultaneously, it would not be possible with prior art devices. A similar problem also exists with one device if it supports more than one communication protocol. Then, accordingly, the media module selects the correct protocol and performs necessary conversions between the portable device and the other device. However, only one communication stream can be active with prior art media modules.